7. Project Summary/Abstract. In the mammalian brain, early sensory areas are organized as stereotyped maps of stimulus qualities. The anatomical features of these sensory maps underlie the neuronal computations and information processing that are essential to generate appropriate perceptual experiences and behaviors. In the mammalian olfactory system primary olfactory sensory neurons (OSNs) expressing the same odorant receptor converge their axons into the same insular glomerular structure in the olfactory bulb. The mitral/tufted cells in the bulb received exclusively input from single glomeruli, but they project to various cortical areas with divergent output patterns. There are also extensive intercortical connections with no apparent anatomical mapping. It is not well understood how this pattern of strict convergence and segregation contributes materially to the processing of olfactory information and odor-driven behaviors. Nor is it understood the role played by the intercortical connections in the process of odor information. In this project, we establish a multi-disciplinary approach to determine the contribution of intercortical connections to odor representation and perception. Specifically, we will use activity marking to determine the stable representation of odors in various cortical areas and test the hypothesis that intercortical interactions stabilize odor representation.